Secure printing systems are typically used for printing secure value documents, e.g., postage, tickets, money orders, etc. Since such documents may have substantial cash value, there exists a continuing problem of preventing the copying of such documents to generate fraudulent documents. To aid in the detection of copies, graphic security features are introduced into the images, including, for example, watermarks, odd print resolutions, specialized inks, etc. Such security features are difficult, if not impossible, to reproduce with typical “off-the-shelf” printers, scanners or copiers. Thus, the security features enable detection of any copies of such secure value documents that have been printed or reproduced by other devices.
Since the security features enable the detection of copies of the secure value documents, it is necessary to ensure that the secure printing systems themselves cannot be used to print fraudulent images which contain the security features. It is therefore necessary to control the source of the images being printed by the secure printing systems, thereby preventing a dishonest person from providing a fraudulent image, e.g., a counterfeit postage indicium, ticket, money order or the like, to the secure printing system, which will print the security features in the fraudulent image, such that it appears legitimate. As a result, such secure printing systems are single purpose devices, i.e., they can only be used to print value documents from a secure source and cannot be used to print any other types of images. This restriction limits the usefulness of such secure printing systems. For example, a postage label printer may be able to print postage and address information, but can not be used to print corporate logos or product labels since the images could be fraudulent copies of valid postage indicia which would be indistinguishable from original valid postage indicia.
Thus, there exists a need for a printing system that can be used to print both secure value documents and non-secure documents while ensuring that fraudulent copies of secure value documents printed by the printing system can be detected.